Scientific Alliance Scotland made a formal complaint about the developer’s claim that the wind farm, which is Europe's biggest onshore wind farm, can power 300,000 homes.
Apart from being anti-wind power, the group is pro-genetically modified foods and against further regulation of the pharmaceutical industry.
Wind developers and manufacturers often make claims concerning the expected output of a project based on the power of the turbines and the average wind speed, commonly applying fixed factors to calculate a percentage of the nameplate power of the installed turbines.
In Whitelee’s case, Scottish Power confirmed that it applied the industry standard capacity factor of 30% to the wind farm’s nominal capacity of 539MW, while assuming an annual household energy use of 4,266KWh.
However, the alliance claims that between 2007 and 2013, Whitelee's rolling load factor was 22.2% of the nameplate power.
When contacted, Scottish Power admitted that it will change its calculations to use site-specific data that indicates a 27% factor over a 25-year period, therefore powering 298,837 homes per year.
Earlier this year, the ASA issued new guidance that stipulates the use of site-specific data wherever possible, rather than an industry standard.
A Scottish Power spokesperson disputed the claims that the estimate should be as low as 22.2%, pointing to the fact that the first stage of the wind farm was not actually connected to the grid in 2007 and was not completed until 2009. The extension was finished earlier this year, bringing the capacity to 539MW from 322MW.
The alliance also questioned the claims concerning household energy use, arguing that, since most homes are heated with gas, the figure should be four times higher.
However, Scottish Power said that it uses an official figure from the UK Department of Energy and Climate Change for its calculations.
A number of issues can limit a wind farm’s operational output including stoppages for maintainance and low or too-high wind speeds. There has been some evidence that claims by developers using a standard factor do not always present an accurate picture of the plant’s output.
If the ASA was to find that Scottish Power had indeed mislead in its predictions, then a precedent would be established that would curtail other company’s ability to make such claims.